432: Difference between revisions

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When the metal covers are removed, one can see the shaping/compensation capacitors.  These can be unplugged, each one has 6 legs.
When the metal covers are removed, one can see the shaping/compensation capacitors.  These can be unplugged, each one has 6 legs.
File:Tek_432_internal_4.jpg
File:Tek_432_internal_4.jpg
Another view of the shaping capacitors.  Work on one channel at a time to avoid mixing these up.
Another view of the shaping capacitors.  Work on one channel at a time to avoid mixing these up. Carefully clean the legs with isopropal alcohol and paper towels. 
File:Tek_432_internal_5.jpg
File:Tek_432_internal_5.jpg
In order to access the rotary gain switch fingers, one must first remove these BNC connectors, which means unsoldering the central wire (connects to a resistor/inductor feed-through) plus a debouce capacitor and lead going to the x1 x10 indicator lights.
In order to access the rotary gain switch fingers, one must first remove these BNC connectors, which means unsoldering the central wire (connects to a resistor/inductor feed-through) plus a debouce capacitor and lead going to the x1 x10 indicator lights.
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View of the input preamp.  This board needs to be unplugged only, but not removed or unsoldered.  It has four 2-pin connectors.  Then it can be removed, still attached to the compensation capacitor carriers.
View of the input preamp.  This board needs to be unplugged only, but not removed or unsoldered.  It has four 2-pin connectors.  Then it can be removed, still attached to the compensation capacitor carriers.
File:Tek_432_internal_10.jpg
File:Tek_432_internal_10.jpg
Lifting off the assembly consisting of the 2 compensation capacitor carrier  plus the vertical preamp board  plus the  push-button switch board for CH1/CHOP/ALTERNATE/CH2.  The switch board has two plug connectors below that must be removed.  It helps to have long fingers or a good pair of needle nose pliers.
Lifting off the assembly consisting of the 2 compensation capacitor carrier  plus the vertical preamp board  plus the  push-button switch board for CH1/CHOP/ALTERNATE/CH2.  The switch board has two plug connectors below that must be removed.  It helps to have long fingers or a good pair of needle nose pliers.
File:Tek_432_internal_11.jpg
File:Tek_432_internal_11.jpg
Second view under the assembly being removed.
Second view under the assembly being removed.
File:Tek_432_internal_12.jpg
File:Tek_432_internal_12.jpg
The rotary switches exposed. Each one has four contact fingers underneath.  They are cleaned using small (5mm) wide strips of paper soaked in isopropanol alcohol (2-propanol).
File:Tek_432_internal_13.jpg
File:Tek_432_internal_13.jpg
One can just see the four contact fingers peeking out.  You can get paper under them using small tweezers.  Patience and calm are required.
File:Tek_432_internal_14.jpg
File:Tek_432_internal_14.jpg
A view of the variable-gain potentiometers. Note that the bodies are both cracked in the same place.  Both had been noisy, but the noise was largely eliminated by sweeping them back and forth a dozen times.  I guess that scrubbed off the oxide.
File:Tek_432_internal_15.jpg
File:Tek_432_internal_15.jpg
A view of the contact fingers underneath the capacitor shaping blocks.  Each channel has 8 NC and 8 NO fingers (the other half are on the bottom).  These are easy to reach and clean as described.  So each channel has a total of 20 contact fingers to clean.
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[[Category:400 series scopes]]
[[Category:400 series scopes]]
[[Category:Specifications needed]]
[[Category:Specifications needed]]
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